Phone of the Day: Mitel 5312 IP Telephone at Four Points Sheraton West Lafayette, IN

Phone of the Day: Mitel 5312 IP Telephone at Four Points Sheraton West Lafayette, IN
I spotted this sleek IP telephone at a not so sleek tired hotel in West Lafayette, IN. Originally a circa 1974 Holiday Inn with a Holidome, I am sure this hotel has seen its share of telephone systems.  I am wondering if this hotel had a Nortel PBX before the Mitel due to the fact ...